The invention relates to a device for sealingly connecting two pipes, said device comprising clamping means bearing on two flanges which, for example, by welding to the facing ends of the pipes.
Numerous connecting or coupling devices of this type are known. In particular, they include altered flange assemblies and couplings with welded end fittings.
In the case of bolted flange assemblies the gasket is either located in a groove formed on the front face of one of the flanges, or is directly secured between the front faces of the flanges. In both cases, locking is brought about by means of bolts or any similar locking or tightening means. When the gasket is positioned in a groove, its fitting and removal make it necessary to move the two flanges apart by a distance substantially equal to the gasket thickness. When the gasket is placed directly between the two flanges, the spacing of the flanges must slightly exceed the gasket thickness in order to permit the fitting thereof.
In the case of couplings with welded conical end fittings, the gasket is fitted by moving apart the two end fittings by a distance equal to the width of the self-centering device of the gasket and the end fittings.
Moreover, in all the known coupling devices, the locking of the gasket is brought about by moving together the two flanges or the two end fittings, for example, by means of locking bolts.
In all the prior art devices, the flanges fixed to the ends of pipes must therefore undergo a number of different movements, both during the introduction and removal of the gaskets and during the tightening of the coupling. These movements lead to stresses in the pipes or the casings of equipment inserted in the circuit. These stresses can be absorbed by using relatively flexible pipes having elbows or expansion bends making it possible to compensate the flange movements. However, it is not always possible to use such pipes and consequently it is not always possible to use the conventional coupling devices. Moreover, even when it is possible to give the pipes a construction and configuration permitting compensation of the movements which have to be carried out by the flanges, these special pipe characteristics make the circuit more complicated and significantly increase costs.